What's the name of Kristy Yang's brother?

(of children) born of the same mother but different fathers.

Gong Ruxin said that the only help their father gave them was to let their mother and daughter immigrate to Canada.

After that, his father didn't give them any help, leaving Yang's mother to raise young Gong Ruxin alone. Even Gong Ruxin didn't care about her 18 birthday. Later, Yang's mother met her stepfather in Canada. He was from China and gave birth to her younger brother.